The present invention relates to a motor vehicle equipped with a system for detecting the approach of a user.
Detection systems of this kind are already used in certain motor vehicles to automatically trigger the unlocking of a door lock, or authorization to open a door, as soon as the user approaches without his having to use a key or remote control. In order to carry out this automatic unlocking before opening the door, use is made of a system generally referred to as a "hands-free access system", which system activates a remote exchange of information between an identifier on the vehicle and identification carried by the user. When the identification has been recognized as correct by the identifier, the lock will be opened, thus allowing the user to open the door simply by pulling on the door handle.
However, it is inconceivable to leave the identification and/or identifier constantly activated because they consume too much electricity. Furthermore, the identification and the identifier must be capable of being activated at any time, because it is not possible to predict when the user will approach the vehicle. It has therefore already been proposed to use a system for detecting approach or gripping of the handle by the user, in order to activate the identifier of the vehicle only when the user is preparing to open the door.
It has thus been proposed to equip the door handles with an electrical contactor to detect the start of the actuation travel of the handle in order to open the door. However, this solution has the drawback of detecting the user's approach too late because the time taken by the identifier to recognize the user's identification correctly and to instruct the lock to be opened is generally much longer than the time taken by the user to complete the actuation travel of the handle. In other words, the door is generally not yet unlocked when the user has completed the actuation travel of the handle, and it is sometimes necessary to actuate the handle several times in order to successfully open the door.
It is also known to use optical or ultrasonic detection systems, but their cost is generally too high.
Document DE No. 196 17 038 describes a motor vehicle having a first electrode integrated with a door-opening handle, a second electrode on the surface of the door, a capacitive detector integrated in the door-opening handle, the capacitive detector being connected by an electrical link to the central control unit, a voltage with opposite poles being applied to the two electrodes and, in order to produce an electric field, between the opening handle and the door, the insertion of the user's hand between the two electrodes modifying the electric field, this modification being measured by the capacitive detector which can thus trigger the interrogation with a view to identifying the user. However, a system of this type needs detection of a modification in the electric field generated between two electrodes, and insertion of the hand between the two electrodes, which delays the detection.
Furthermore, all the solutions currently known need extra electrical connections between the handle and another element of the door.